NTSC is just one specific implementation of analog color video transmission, has nothing to do with CRT functionality outside of North America/Japan/a few other

NTSC is just one specific implementation of analog color video transmission, has nothing to do with CRT functionality outside of North America/Japan/a few other places and generally when speaking about CRT monitors for computers, arcades and the like they operate on discrete RGB signals with a wide variety of timing: https://en.wikipedia.org/wiki/Coordinated_Video_Timings https://en.wikipedia.org/wiki/Coordinated_Video_Timings, NTSC isn't a thing. Furthermore, even when using NTSC video timings, the 3.58 MHz subcarrier is specific to transmission of composite video (carrying brightness and color combined in the same signal). A DVD player for instance with a component or SVideo output produces NTSC timing but there is no subcarrier because the color signal is discrete.